Up to now, a signal processing apparatus has been proposed in which a plurality of circuit substrates are connected via an optical waveguide, and a signal can be sent and received by way of light between respective substrates (for example, see Japanese Unexamined Patent Application Publication No. 10-123350).
In the traditional signal processing apparatus, a plurality of substrate connectors are provided to a support substrate to which the optical waveguide is mounted, and as the circuit substrate is mounted to the substrate connector, the plurality of circuit substrates are connected to the optical waveguide.
Also, in the support substrate, an electric wiring for electric signal transmission is provided, and the sending and receiving of the electric signal are also carried out between the circuit substrates.